<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>


<script>

    //判断语句  如果
    // if(条件){
    //     满足条件才执行的代码
    // }

    var a = 100;
    if (5 > a) {
        console.log('成立');
    }
    console.log(a);
    //  -------------------------

    if (5 > a) {

        a = 666;
        console.log('满足了if')
    } else { //  5 <= a  //否则  , 是对 if后面的条件取反 , 判断是否满足
        a = 999;
        console.log("满足了else")
    }

    console.log(a);
    //    -------------------------

    if( a > 18){  //a>18

    }else if(a == 18){   //a = 18

    }else{ // a < 18  --->  >10?
        if(a > 10){
            console.log('a<18  &&  a>10')
        }else{
            console.log("a<18  &&  a<= 10 ")
        }
    }


</script>
</body>
</html>
